Metal-to-wood fastening for railway ties



Oct. 5, 1954 J. R. SNYDER METAL-TO-WOOD FASTENING FOR RAILWAY TIES FiledMay 25, 1948 2 Sheets-Sheet l W Arm/W575 if m w M, M; a w w. R. s a m wP u -"w l L M Wallis 7 H 1 mm m 7. 3

Oct. 5, 1954 J. R. SNYDER METAL-TO-WOOD FASTENING FOR RAILWAY TIES FiledMay 25, 1948 2 Sheets-Sheet 2 a N Is 7 INVENTOR.

J2me 191/5 1 SNYDER A 7' TOR IVEYJ Patented Oct. 5, 1954 await STATESATENT OFFICE METAL-TO-WOOD FASTENING FOR RAILWAY TIES 22 Claims.

This invention relates to metal-to-wood fastenings of the type in whicha metal fastener such as a spike or lag screw is driven into a woodmember and relates, more particularly, to an improved fastening of thiskind in which a stronger and more durable connection is obtained betweenthe metal fastener and the wood member.

Although the improved metal-to-wood fastening provided by the presentinvention can be applied to numerous different specific uses, it isparticularly valuable in railroad construction and for that reason ishereinafter described as applied to that use. The disclosure of theimproved fastening as applied to railroad construction represents onepractical embodiment of the invention and is not made with any intent tolimit the invention to that particular use.

Considerable difficulty has been encountered heretofore in railroadconstruction in that track fastenings are subject to rapid deteriorationand loosening. Fastenings of this kind are subject to adverse serviceconditions by reason of the fact that they are constantly exposed toweather effects and to corrosive brine, and the like, which drips fromrailroad cars. These fastenings are also subject to constant jarring andvibration during the passage of trains on the track, as well as tolifting forces resulting from repeated defiection of the rails under theweight of passing railroad cars. Such jarring, vibration and liftingforces tend to loosen the spikes in the wood ties, which permits waterand brine to enter the spike holes and further promote corrosion of thespikes and rotting of the ties. Moreover, when loosening of the spikeshas occurred, it creates a hazardous condition which may result in atrain wreck and also produces a condition which is very destructive tothe ties because the loose fastenings permit increased flexing of therail and this results in pounding and cutting of the ties by the tieplates. Still other factors which result in loose or weak fastenings aresplitting of the ties and shearing of the wood in the spike holes whenexcessive torque is used in driving screw spikes.

One way of dealing with this problem is offered in my earlier Patent No.2,389,464, granted November 20, 1945, in which the spike holes of woodties are treated with a preservative material, such as asphalt orcreosote, and although this treatment is highly beneficial it does notprevent the spikes from working loose. Another attempt to meet some ofthese disadvantages consists in the use of rustproofed spikes, such asgalvanized spikes, and although the rustproofing decreases corrosion, italso gives the spikes a smoother surface characteristic which materiallydecreases their holding power in the wood ties.

The present invention satisfactorily overcomes all of theabove-mentioned difficulties and it can accordingly be said that, as oneof its objects, this invention provides an improved metal-to- Woodfastening in which increased holding power and durability are obtained.

Another object is to provide an improved fastening of this character inwhich increased holding power and durability are obtained by reason ofthe fact that the wood member has been chemically treated and hardened.

A further object of this invention is to provide an improved fasteningof the type comprising a metal fastener driven into a preformed bore ofa wood member and in which a water-insoluble cold-setting glue increasesthe strength of the fastening by accomplishing the dual purpose ofreinforcing the wood member and establishing an adhesive bond with themetal fastener.

Still another object is to provide an improved fastening of this kindhaving increased strength and durability by reason of the fact that thewood member has been impregnated with a woodhardening and -preservativematerial, preferably a thermosetting material, although a thermoplasticmaterial or a combination of thermosetting and thermoplastic materialscan be used.

Yet another object is to provide an improved fastening of the charactermentioned in which the wood-hardening and -preservative material is aresin type of glue which also establishes an adhesive bond between themetal fastener and the wood member.

As another of its objects, this invention provides an improved railfastening in which a connection formed between a wood tie and a metalspike driven thereinto has increased holding power and durability due tothe impregnation of the tie, or the portion thereof immediatelysurrounding the spike, with a water-insoluble cold-setting glue which isalso a wood-hardening and -preservative material, such material beingpreferably a thermosetting resin, although a thermoplastic material or acombination of thermoplastic and thermosetting materials can be used.

As a further object this invention provides a novel metal-to-woodfastening of this character in which the glue or wood-hardening and-preservative material comprises a mixture of a synthetic resin of thealdehyde or phenol aldehyde class and a vinyl resin and which mixture isrendered thermosetting by the mixture of a hardener or catalysttherewith.

This invention also provides, as another of its objects, the novel useof capsule means by which the treating material or glue for theabovementioned metal-to-wood fastenings can be introduced into apreformed bore of a wood member.

Other objects and advantages of this invention will be apparent in thefollowing detailed description and in the accompanying sheets ofdrawings in which,

Fig. 1 is a partial vertical section taken through a railroad trackconstruction embodying the present invention, the view being takenlongitudinally through a wood tie and transversely of rail and stringermembers connected to the tie;

Fig. 2 is a plan view of a portion of the track construction of Fig. 1and showing the rail and tie plate supported on the wood tie;

Fig. 3 is a partial vertical section similar to Fig. l, but showing thespikes only partially driven into the tie;

Fig. 4 is another partial vertical section showing the treating materialcontained in capsule means adapted to be broken during the drivin of thespikes;

Fig. 5 is another such partial vertical section, but showing a differentform of capsule means for the treating material, and

Figs. 6 and 7 are transverse sectional details taken respectively onsection lines 5-6 and '!-'F of Fig. 1.

Proceeding now with a more detailed description of the invention,reference will first be made to Figs. 1 and 2 of the drawings which showa typical form of railroad track construction having the presentinvention embodied therein. The railroad track construction hereillustrated includes a wood tie I!) having a conventional tie plate Hmounted thereon and supporting a conventional rail I2 of the type havinga head Ifla and a base flang I212. The tie plate H is secured to the tieID by means of conventional screw spikes l3 and the rail I2 is heldagainst the tie plate H by means of conventional cut spikes i l. Therailroad track construction here shown also includes a Wood member orstringer I 5 extending transversely of a number of the ties adjacent theend thereof and connected to the tie it by a screw spike [G of the kindcommonly referred to as a lag screw.

The tie it is a wood member such as a tie sawed or otherwise preparedfrom oak, pine or other kind of wood timber. The tie may have its outersurface creosoted as is conventional practice in present day railroadconstruction. The tie plate II has spaced openings I! and I8 thereinwhich accommodate the spikes E3 and it, and the tie It has preformedopenings or bores i9 and located so as to register with the openings ofthe tie plate and into which the spikes l3 and Hi are driven,respectively.

The spike I3 is a conventional screw spike having a square head 22carrying a shoulder 23 and also having a tapered stem 2d carrying ahelical screw thread 25. The stem portion 28 immediately adjacent thehead 22 can be cylindrical in shape, but for a purpose to be explainedhereinafter, the stem portion 21' located immediately below thecylindrical portion 26 is a tapered portion. The preformed bore l9 intowhich the screw spike i3 is driven is of a diameter slightly larger thanthe root diameter of the screw spike but smaller in diameter than thediameter of the screw spike measured across the tops of the threadconvolutions.

The spike Hi is a cut spike of conventional form having a head 28 whichincludes an offset portion overlying the rail flange I21), and alsohaving a stem 29 of a substantially square crosssection which isprovided at its lower end with a chisel point 30. The preformed bore 20into which the spike I l is driven is of a smaller diameter than theminimum transverse dimension of the spike, as illustrated in Fig. '7.

As shown in Fig. l, the tie I0 is also provided with a preformed bore 3|into which the lag screw it is driven and the stringer I5 is providedwith an opening 32 which is aligned with the bore of the tie andaccommodates the cylindrical upper portion 33 of the stem of the lagscrew. The lag screw I6 is provided at its upper end with a square head34 carrying a shoulder 35 and the lower portion of the lag screw carriesa helical thread 36. The intermediate portion 31 which connects thethreaded lower stem portion of the lag screw with its cylindrical upperstem portion 33 is tapered for the same purpose as the taper 27 providedon the screw spike l3.

An important feature of the present invention resides in the fact thatthe tie ID, or the portions thereof immediately surrounding the boresi9, 20 and SI, is impregnated with a woodhardening and -preservativematerial which in creases the strength and durability of the connectionsformed between the metal fastenings 53, it, it and the wood tie. In somecases the entire tie it, or a substantial portion thereof, will beimpregnated with the wood-hardening and -preserva-tive material and suchcomplete or partial impregnation can be prior to or after the formationof the bored holes in the tie. This complete or partial impregnation ofthe tie can be accomplished by forcing the treating material into thetie in accordance with the method and apparatus disclosed in co-pendingapplication, Serial No. 29,133, filed May 25, 1948, now abandoned. Inother cases only the portions of the tie immediately surrounding thepreformed bores I9, 20 and 3| are impregnated with the treating materialand this is accomplished by a pressurizing of the material in the boresby the fasteners during the driving of the latter, as is explainedhereinafter. When the fasteners l3, l4 and i6 are to be driven intobores formed in a wood tie which has been previously treated with thewood-hardening and -preservative material, a small additional amount ofthis material is introduced into the bores at the time of the driving ofthe fasteners thereinto for establishing an adhesive bond between thefasteners and the treated tie.

Fig. 1 of the drawings illustrates the case in whi h the treatingmaterial has been placed in the bores I9, 26 and 3l and is subjected topressure during the driving of the fasteners l3, l4 and I6 for causingsuch material to impregnate the portions of the tie immediatelysurrounding the bores. The treating material has been designated in thebores 19, 20 and 31 by the reference character 39 and although portionsof this material are shown remaining in the bores, it will be understoodthat other portions of this material form a coating on the fasteners andstill other portions have been forced laterally into the pores of thewood tie l0. When the treating material 39 is placed in the bores i9, 28and 3|, it is in a plastic or liquid state and during the driving of thefasteners, this material is trapped in the bores and is subjected topressure. In the case of the threaded fasteners l9 and 3|, the trappingand pressurization of the treating material is accomplished by theengagement of the tapered portions 21 and 37 in the bores l 9 and 3!. Inthe case of the cut spike I l, the treating material is trapped in thebore 'by the engagement of the square cross-section of the spike in thesmaller diameter bore 20.

After the fasteners have been driven into the tie in, the treatingmaterial 39 assumes a set or hardened condition in which it bonds withthe wood and reinforces those portions of the tie immediatelysurrounding the fasteners and also forms an adhesive bond between thetie and the fasteners. The hardening of the wood around the bores intowhich the fasteners are driven renders the wood substantiallynon-absorbent and highly resistant to subsequent rotting or splitting.The setting of the material in these portions of the tie also greatlyincreases the holding power of the fasteners in the tie by preventingshearing or stripping of those portions of the tie in which the screwthreads engage. The adhesive bond which the treating material formsbetween the tie and the threaded fasteners also holds the fastenersagainst turning movement and thus prevents loosening of the fasteners.In the case of the cut spike I l, the adhesive bond formed by thetreating material holds the spike against upward movement in the bore 20and the hardening of the wood surrounding this bore increases theresistance which, the tie is able to offer to lateral shifting of thecut spike.

Various chemical materials can be used as the treating material 39, butin general the material employed for this purpose should be initiallyfluid or plastic and should have setting characteristics such that inits set condition it will be water-insoluble and substantiallynon-absorbent and will harden or reinforce the wood and render the sameresistant to fraying, shearing or rotting. As this treating material,any one of various synthetic resins can be used, such as resins of thealdehyde or phenol aldehyde class, for example, phenol formaldehyde,urea formaldehyde, melamine formaldehyde or resorcinol formaldehyde.These materials are potentially thermosetting in character and arerendered actually thermosetting by the mixing of a hardener or so-calledcatalyst therewith, such as formaldehyde, and the mixture formed by theresin and the catalyst constitutes the treating material 39. Thecatalyst can be in either powdered or liquid form and is added to theresin in suitable amounts such as 5 per cent to per cent by weight to 95to 50 per cent by weight of the resin but the amount of the catalyst tobe used will depend upon the setting characteristics desired for thetreating material. Ordinarily an amount of the catalyst is employedwhich will produce setting of the resin in a period of from one to fourhours at normal temperature, that is to say, a temperature ranging fromdegrees to 90 degrees Fahrenheit.

An important feature of the present invention is that the treatingmaterial 39 also establishes an adhesive bond between the wood and themetal fasteners driven thereinto. It is also important to prevent thetreating material 39 from assuming a brittle state in which cracking orcrazing might result in the material after it has set. Both of thesecharacteristics are obtained by incorporating a plasticizing agent, suchas a suitable thermoplastic material, in the aldehyde resin prior to themixing of the catalyst therewith. As this plasticizing agent a vinylresin can be used such as vinyl acetate or vinyl butyral. The preferredplasticizing agent can be designated as a partially hydrolized polyvinylacetate. Suitable amounts of the plasticizer can be used depending uponthe setting characteristics desired for the resin and when theabove-mentioned polyvinyl acetate is used as the plasticizer, 2 per centto 20 per cent by weight is added to the resin. The treating material orglue then comprises, by weight, 93 to 30 per cent of the aldehyde resin,2 to 20 per cent of vinyl resin and 5 to 50 per cent of the catalyst.

To illustrate the effectiveness of the treating material 39 inincreasing the strength of the connection formed between the tie I0 andthe metal fasteners driven thereinto, the following tabulations aregiven showing the results of actual tests which have been carried out.

(A) Torque tests on metal-to-wood astem'ngs Pull resistance in Lbs. TestMetal Fastener gr Bore With- With out Glue Glue 1. %5 Screw Spike.RedOak. ,4 5%. 17,850 13, 700 2.... is Screw Spike... ...do..... lia x5%- 20, 500 13, 800 3-- is" Out Spike.. Pinc..... Wx59..- 3,400 2, 2004. ..do RedOB-lL. We): 5% 5, 375 3,000 .d0. .d 9'i6x5}. 6,900 3,125 946"592%. 9,290 3,050

In the tests of the above tabulations the wood ties used were creosotednew wood ties having the bores formed therein after the ties had beencreosoted. The glue as used in these tests consisted of a mixture of apotentially thermosetting resin and formaldehyde as a hardener orcatalyst. Torque tests Nos. 1 to 6 inclusive of tabulation (A) and pulltests Nos. 1 to 4 inclusive of tabulation (B) were performed onmetal-to-wood fastenings which had been formed by the use of a gluecomprising a mixture of parts by weight of a liquid potentiallythermosetting resin, namely resorcinol formaldehyde, and 30 parts byweight of powdered formaldehyde as a hardener or catalyst. Pull testsNos. 5 and 6 of tabulation (B) were performed on metal-to-woodfastenings which had been formed by the use of a glue comprising 100parts by weight of a liquid potentially thermosetting resin, namelyresorcinol formaldehyde, 15 parts by weight of liquid formaldehyde as ahardener or catalyst, and vinyl acetate in the amount of 10 parts byweight for test No. 5 and 15 parts by weight for test No. 6. In all ofthe tests of tabulations (A) and (B) the glue was introduced 7 into thebores and was pressurized into the wood by the driving of the spikesthereinto and the glue was permitted to assume a set condition beforethe test forces were applied to the fasteners.

Fig. 3 of the drawings shows the improved fastening being formed by thedriving of the spikes l3 and I4 into the bores l9 and 20 in whichquantities of the treating material 39 in bulk form have been placed.During the driving of the spikes the treating material is subjected topressure, as explained above, and is forced into the pores of the woodtie it.

Fig. 4 shows the treating material contained in capsule means so as torender this material convenient to handle for introducing the same intothe bores l9 and 20. The capsule means here shown comprises an outercapsule 30 containing a quantity of the treating material til, that isto say, a quantity of a potentially thermosetting resin as mentionedabove, or a mixture of such resin and a plasticizer as mentioned above.The capsule means also includes an inner capsule 42 containing thecatalyst material 43 and maintaining the catalyst segregated from theresin. The capsules 40 and 42 can be made of any suitable material, suchas a molded plastic capable of resisting any chemical action thereon bythe materials contained therein. Fig. 4 shows the screw spike 13 aboutto be started into the bore l9 and which inward movement of the screwspike causes rupturing of the capsules and a mixing of the catalyst withthe resin to render the resin thermosetting. Fig. 4 also shows the cutspike l4 partially driven into the bore 20 and as having alreadyruptured the capsules ll! and 42 contained therein.

Fig. of the drawings illustrates another form of capsule means in whicha main capsule 25 contains the potentially thermosetting resin 25, or amixture of such resin and plasticizer, and a supplemental capsule 41contains a quantity of the catalyst 48 in powdered form. The capsulemember l! is here shown in the form of a cap which is telescopinglymounted on one end of the main capsule '45. Fig. 5 shows the cut spikeId about to be driven into the bore 2!] in which the capsule has beeninserted. The movement of the pointed lower end of the spike into thebore will rupture the capsule and cause mixing of catalyst powder 48with the fluid resin 55 and will render the latter thermosetting.

In the tabulations given above the values representing the increasedholding power of the metal fasteners in the tie [0 resulting from theuse of the treating material 39 are the values obtained when thefasteners were subjected to torque tests and pull tests for the initialremoval of the fasteners from the connection. It has been found,however, that when the fasteners are removed from the tie, as for thepurpose of replacing the rail [2 and are again driven into the samebores of the tie, the fasteners will still have a substantiallyincreased holding power in the tie. When the fasteners are thus redriveninto the same bores of the tie, additional amounts of the treatingmaterial 39 can be used and holding values for the fasteners comparablewith, or greater than, those expressed in the above tabulations willagain be obtained.

From the foregoing description and the accompanying drawings, it willnow be readily understood that this invention provides an improvedmetal-to-wood connection by which the holding power and durability forfastenings formed between a wood member and a metal fastener driventhereinto will be greatly increased. It will now also be understood thatthe increased holding power and durability for the fasteners is derived,in part, from a hardening and strengthing of the wood member and, inpart, from an adhesive bond established between the metal fasteners andthe wood member. Additionally, it will be seen that the improvedfastening provided by this invention is especially valuable in railroadtrack construction and will contribute materially to the longer life ofwood ties.

Although the improved fastening provided by this invention has beenillustrated and described herein to a detailed extent, it will beunderstood, of course, that the invention is not to be regarded asbeinglimited correspondingly in scope, but includes all changes andmodifications coming Within the terms of the claims hereof.

Having thus described my invention, I claim:

1. A fastening of the character described comprising, a wood memberhaving a preformed bore therein, a metal fastener engaging in said borewith a relatively close fit such that portions of said fastener are indirect contact with the side wall of said bore, and an initially fluidthermosetting resin in a set condition forming an adhesive bond betweensaid fastener and said wood member internally of the latter.

2. A fastening of the character described comprising, a wood memberhaving a preformed bore therein, and a metal fastener engaging in saidbore with a relatively close fit such that portions of said fastener arein direct contact with the side wall of said bore, the portion of saidwood member immediately surrounding said bore being impregnated with aninitially fluid woodhardening and -preservative thermosetting resinmaterial which in its set condition hardens the impregnated portion ofsaid wood member and renders the same stronger and more durable, saidfastener having increased resistance to lateral shifting and axialloosening movements in said bore by reason of its tight fitting directengagement with said impregnated and hardened portion of said woodmember.

3. A fastening of the character described comprising, a wood railway tiehaving a preformed bore therein, and a metal fastener of the railfastening spike type engaging in said bore with a relatively close fitsuch that portions of said fastener are in direct contact with the sidewall of said bore, the portion of said wood member immediatelysurrounding said bore and substantially coextensive therewith beingimpregnated with a thermosetting resin which is initially fluid and inits set condition hardens the impregnated portion and increases thestrength and durability of the connection between said fastener and saidwood member.

4. A fastening of the character described comprising, a wood memberhaving a preformed bore therein, and a metal fastener engaging in saidbore with a relatively close fit such that portions of said fastener arein direct contact with the side wall of said bore, the portion of saidwood member immediately surrounding said bore being impregnated with athermosetting resin which is initially fluid and in its set condition inthe impregnated portion hardens the same for increasing the strengthanddurability of the connection between said fastener and said wood memher,the set resin also forming an adhesive bond. between said fastener andsaid wood member internally of the latter.

5. In a fastening of the character described, a wood member having apreformed bore therein, and a metal fastener of the cut spike typedriven into said bore and having a relatively tight fittingmetal-to-Wood engagement with the portion of said wood memberimmediately surrounding said bore, such surrounding portion beingimpregnated with an initially fluid but settable water-insolublewood-hardening and -preservative synthetic resin material which in itsset condition hardens and preserves the impregnated portion and alsoforms an adhesive bond between said spike and wood member, said materialbeing initially contained in said bore and the bore being of a smallerdiameter than the minimum transverse dimension of said spike such thatduring the driving of said spike said material will be trapped andpressurized thereby in said bore and forced into the portion of the woodmember immediately surrounding said bore.

6. In a rail fastening, a wood tie having a preformed bore therein, atie plate on said tie and having an opening aligned with said bore, arail on said tie plate, and a screw spike extending through the openingof said tie plate and driven into said bore and having a relativelytight-- fitting metal-to-wood engagement with the portion of said tieimmediately surrounding said bore and substantially coextensivetherewith, such surrounding portion being impregnated with and havingdistributed therein a thermosetting resin in a set condition, said resinbeing initially fluid in said bore and being forced into saidsurrounding portion of said tie by the driving of said spike into saidbore.

'7. In a rail fastening, a wood tie having a preformed bore therein, atie plate on said tie and having an opening aligned with said bore, arail on said tie plate, and a screw spike extending through the openingof said tie plate and engaging in said bore with a relatively close fitsuch that portions of said screw spike are in direct contact with theside wall of said bore, the portion of said tie immediately surroundingsaid bore being impregnated with an initially fluid thermosettingwood-hardening and -preservative synthetic resin material, said materialin its set condition rendering the impregnated portion harder and moredurable and also forming an adhesive bond between said screw spike andsaid tie.

8. In a rail fastening, a wood tie having a preformed bore therein, atie plate on said tie and having an opening aligned with said bore, arail on said tie plate, and a cut spike extending through the opening ofsaid tie plate and engaging in said bore with a relatively close fitsuch that portions of said out spike are in direct contact with theportion of said tie immediately surrounding said bore, such surroundingportion being impregnated with an initially fluid thermosettingwood-hardening and -preservative synthetic resin material which in itsset condition renders the impregnated portion harder and more durableand also forms an adhesive bond between said spike and tie.

9. In a fastening of the character described, a wood member having apreformed bore therein and the portion of said wood member immediatelysurrounding said bore being impregnated with a thermosettingwood-hardening and -preservative chemical, and a metal fastener driveninto said bore and forming with the impregnated portion of said woodmember a connection of increased strength and durability, said chemicalcomprising a potentially thermosetting resin material and a catalystmaterial and being initially contained in a capsule means of a size tobe received in said bore, said capsule means having separatecompartments adapted to contain the resin and catalyst materials insegregated relation but being adapted to be broken by the driving ofsaid spike to permit mixing of said resin and catalyst materials.

10. In a fastening of the character described, a wood member having apreformed bore therein and the portion of said wood member immediatelysurrounding said bore being impregnated with a thermosettingwood-hardening and -preservative chemical, and a metal fastener driveninto said bore and forming with the impregnated portion of said woodmember a connection of increased strength and durability, said chemicalcomprising a potentially thermosetting resin material and a catalystmaterial, one of which materials is contained in a capsule of a size tobe received in said bore and the other of said materials being containedin a second capsule located inside the first-mentioned capsule, saidcapsules being adapted to be broken by the driving of said spike topermit mixing of said resin and catalyst materials.

11. A fastening of the character described comprising, a wood memberhaving a preformed bore therein, a metal fastener engaging in said borewith a relatively close fit such that portions of said fastener are indirect contact with the side Wall of said bore, the portion of the woodmember immediately surrounding said bore being impregnated with aninitially fluid water-insoluble cold-setting synthetic resin glue whichin its set condition hardens and reinforces said impregnated portion ofthe wood member and establishes an adhesive bond between the impregnatedportion and said metal fastener.

12. A fastening of the character described comprising, a wood memberhaving a preformed bore therein, a metal fastener engaging in said borewith a relatively close fit such that portions of said fastener are indirect contact with the side wall of said bore, the portion of the woodmember immediately surrounding said bore being impregnated with aninitially fluid waterinsoluble cold-setting synthetic resin glue whichin its set condition reinforces said portion of the wood member andestablishes an adhesive bond with said metal fastener, said gluecomprising a mixture of a synthetic resin of the aldehyde class and avinyl resin and said mixture being rendered thermosetting by theaddition of a hardener catalyst thereto.

13. The method of making metal-to-wood fastenings of the kind in which ametal fastener engages in a wood member, which comprises the steps offorming in the wood member a bore of a smaller diameter than thetransverse size of a given metal fastener to be driven thereinto,introducing into said bore a quantity of settable woodhardening and-preservative material in fluid form, driving said given fastener intosaid bore and thereby pressurizing the fluid material therein andcausing said material to impregnate portions of said wood membersurrounding said bore, and permitting said material to assume a setcondition in which it hardens and preserves the impregnated portions ofsaid wood member and increases the holding power of said fastenertherein.

14. The method of making metal-to-wood fastenings of the kind in which ametal fastener engages in a wood member, which comprises the steps offorming in the wood member a bore of a smaller diameter than thetransverse size of a given metal fastener to be driven thereinto,introducing into said bore a quantity of settable wood-hardening and-preservative glue in fluid form, driving said given fastener into saidbore and thereby pressurizing said glue therein and causing said glut toimpregnate portions of said wood member surrounding said bore andsubstantially coextensive therewith, and permitting said material toassume a substantially waterinsoluble set condition in which it hardensand preserves the impregnated portions of said wood member and alsoforms an adhesive bond between the fastener and said wood member.

15. In a method of making metal-to-wood fastenings of the kind in whicha metal fastener engages in a wood member, the steps of forming in thewood member a bore of a smaller diameter than the transverse size of agiven metal fastener to be driven thereinto, introducing into said borea quantity of thermosetting resin in fluid form, and driving said givenfastener into said bore and thereby pressurizing the fiuid resin thereinand causing said resin to impregnate portions of said wood membersurrounding said bore.

16. The method of making fastenings as defined in claim 15 in which saidthermosetting resin comprises a synthetic resin of the aldehyde class.

17. The method of making fasteings as defined in claim 15 in which saidthermosetting resin comprises a mixture of synthetic resin of thealdehyde class and a catalyst for causing the resin to set.

18. The method of making fastenings as defined in claim 15 in which saidthermosetting resin comprises a mixture of synthetic resin of thealdehyde class, a, plasticizer and a catalyst for causing the resin toset.

7.9. The method of making metal-to-wood fastenings of the kind in whicha metal fastener engages a wood member, which comprises the steps offorming in the wood member a bore extending cross-wise of the grain ofthe wood and of a smaller diameter than the transverse size of a givenmetal fastener to be driven thereinto, introducing into said bore aquantity of thermosetting resin in fluid form, driving said givenfastener into said bore and thereby pressurizing the fluid resin thereinand causing said resin to impregnate portions of said wood membersurrounding said bore, and permitting said resin to assume a setcondition.

20. The method of making fastenings of the character described whichcomprises the steps of, forming in a wood member a bore which extendsthereinto cross-wise of the grain and is closed at its inner end,introducing into said bore a quantity of thermosetting resin in fluidform, driving a metal fastener into said bore in tight fittingengagement with the side walls thereof and substantially trapping thefluid resin in said bore and forcing a substantial portion of the fluidresin into the portion of the wood member surrounding said bore andsubstantially coextensive therewith, and permitting the resin to assumeits set condition in which it ha-rdens and preserves the impregatedportion and forms an adhesive bond between the fastener and said woodmember.

21. The method of making metal-to-wood fastenings of the kind in which ametal fastener engages in a wood member, which comprises the steps offorming in the wood member a bore of a smaller diameter than thetransverse size of a given metal fastener to be driven thereinto,providing a capsule means containing a thermosetting resin in fluidform, introducing said capsule means into said bore, driving said givenmetal fastener into said bore and rupturing said capsule means andpressurizing the fluid resin in the bore and causing the resin toimpregnate portions of said wood member surrounding said bore, andpermitting the resin to assume a set condition.

22. The method of making fastenings of the character described whichcomprises the steps of, forming in a wood member a bore which extendsthereinto cross-wise of the grain and is closed at its inner end,providing a capsule means having one compartment containing apotentially thermosetting resin in fluid form and a second compartmentcontaining a catalyst for causing the resin to set when mixed therewith,introducing said capsule means into said bore, driving a metal fastenerinto said bore in tight fitting engagement with the side walls thereofand rupturing said capsule means to liberate and cause mixing of saidfluid resin and said catalyst, the driving of said fastener also causingpressurization of the mixture of fluid resin and catalyst in the boreand impregnation of the portion of said Wood member surrounding saidbore with said mixture, and permitting said resin and catalyst mixtureto assume a set condition in which it hardens and preserves theimpregnated portion of the wood member and forms an adhesive bondbetween the fastener and said wood member.

References Cited in the file of this patent UNITED STATES PATENTS

